Theoretical investigation on vibrational spectra, first order hyperpolarizability and NBO analysis of 4-Phenylpyridinium hydrogen squarate

Theoretical study on 4PHS molecule in the ground state shows the presence of C-H⋯O and N-H⋯O hydrogen bonding interaction. The high βtot value and the low HOMO-LUMO energy gap are responsible for the optical and electron-transfer properties of 4PHS molecule, which indicates that 4PHS molecule is an excellent organic candidate of photon-responsive materials.